JPWO2017073552A1 - Automatic transmission - Google Patents

Abstract

The automatic transmission includes a first engagement element (C1) interposed in the first power transmission path (a1), and an input shaft (30) and a gear train (50) in the second power transmission path (a2). And the second engagement element (C2) interposed between the second engagement element (C2) and the second engagement element (C2) on the wheel (8L, 8R) side in the second power transmission path (a2). A third engagement element (TWC). The first engagement element (C1) includes a continuously variable transmission mechanism (40) and a connecting portion on the wheel (8L, 8R) side of the second power transmission path (a2) with respect to the first power transmission path (a1). And can be switched to an engaged state during forward traveling, a released state during backward traveling, and a released state during inertial traveling. At least one of the second engagement element (C2) and the third engagement element (TWC) is switched to the released state during forward travel, and both are switched to the engaged state during reverse travel.

Description

  The present invention relates to an automatic transmission including a continuously variable transmission mechanism capable of continuously variable transmission while drivingly connecting a drive source and wheels, for example.

  Conventionally, automatic transmissions for vehicles equipped with a continuously variable transmission mechanism such as a belt-type continuously variable transmission mechanism (CVT) have become widespread. As an automatic transmission equipped with a belt-type continuously variable transmission mechanism, for example, one in which a forward / reverse switching mechanism is interposed between a primary pulley of the belt-type continuously variable transmission mechanism and an internal combustion engine is known. However, in this automatic transmission, it is necessary to reduce the load on the internal combustion engine because the clamping pressure of the belt-type continuously variable transmission mechanism is required in both cases of forward travel and reverse travel. In view of this, an automatic transmission has been developed that uses a gear train exclusively for reverse travel to fix the gear ratio so that a belt-type continuously variable transmission mechanism is not used during reverse travel. Examples of such an automatic transmission include an input shaft that is drivingly connected to an internal combustion engine, an output shaft that is drivingly connected to wheels, a belt-type continuously variable transmission mechanism that can connect the input shaft and the output shaft, and an input A gear train that can connect a shaft and an output shaft is known (see Patent Document 1). In this automatic transmission, an input shaft, a connection / disconnection mechanism with a gear train, a forward clutch, and a primary pulley are sequentially arranged on a first shaft, and a secondary pulley and a reverse gear are arranged on a second shaft parallel to the first shaft. The clutch and the output shaft are arranged in this order.

  In this automatic transmission, when moving forward, the forward clutch is engaged to connect the input shaft and the continuously variable transmission mechanism, the connection mechanism is disconnected to disconnect the input shaft and the gear train, and the reverse clutch By releasing the gear train from the output shaft, the rotation of the input shaft is transmitted to the output shaft via the forward clutch and the continuously variable transmission mechanism. In this automatic transmission, when the vehicle is moving backward, the forward clutch is disengaged and the input shaft and the continuously variable transmission mechanism are disconnected, the connection and disconnection mechanism is connected and the input shaft and the gear train are connected. By connecting the gear train and the output shaft with the clutch engaged, the rotation of the input shaft is transmitted to the output shaft through the connection / disconnection mechanism, the gear train, and the reverse clutch. According to this automatic transmission, it is possible to transmit the driving force without going through the continuously variable transmission mechanism at the time of reverse travel, so that no clamping pressure is required and the load on the internal combustion engine can be reduced.

JP-A-63-57957

  However, in the automatic transmission described in Patent Document 1, since the secondary pulley and the output shaft are directly connected, the vehicle that is traveling forward decelerates to run at a low speed, and the idling stop control is executed to execute the internal combustion engine. In order to prevent the mechanical oil pump from stopping and the clamping pressure of the continuously variable transmission mechanism from being reduced and the belt slipping when stopped, for example, an electric oil pump must be used to generate the clamping pressure. I had to.

  Therefore, while it is possible to switch between forward travel using a continuously variable transmission mechanism and reverse travel using a gear train without using a continuously variable transmission mechanism, pinching pressure is generated by stopping the drive source during idling stop control. An object of the present invention is to provide an automatic transmission that does not require another clamping pressure generator such as an electric oil pump even if it is lost.

  An automatic transmission according to the present disclosure includes an input shaft that is drivingly connected to a drive source of a vehicle, an output shaft that is drivingly connected to wheels, a continuously variable transmission mechanism that can continuously change a gear ratio, and the input shaft. And the output shaft are connected to each other via the continuously variable transmission mechanism. The first power transmission path connects the power transmission by switching to the engaged state during forward traveling and the released state during backward traveling. One engagement element, the continuously variable transmission mechanism and the drive source side of the first engagement element in the first power transmission path, the continuously variable transmission mechanism and the wheels of the first engagement element. In a second power transmission path that connects the two sides to each other via a gear train, the second power transmission path is interposed between the input shaft and the gear train, and is switched to an engaged state during reverse travel to disconnect power transmission. Two engaging elements and the second power transmission path It is interposed on the wheel side of the second engagement element, and is powered by switching to the released state at least when the second engagement element is in the engaged state during forward traveling and to the engaged state during the backward traveling. A third engagement element for connecting and disconnecting transmission, wherein the first engagement element includes the continuously variable transmission mechanism and the wheel of the second power transmission path with respect to the first power transmission path. And a connecting portion on the side, and can be switched to a released state during inertial running.

  According to the present automatic transmission, the first engagement element is located between the continuously variable transmission mechanism and the connecting portion on the wheel side of the second power transmission path with respect to the first power transmission path, and has inertia. When traveling, it can be switched to the released state. Therefore, during idling stop control before stopping during deceleration, switching the first engagement element to the released state stops the drive source and continuously variable transmission mechanism while the wheels rotate, so the continuously variable transmission mechanism The belt can be prevented from slipping. As a result, it is possible to switch between forward travel using the continuously variable transmission mechanism and reverse travel using the gear train without using the continuously variable transmission mechanism, while holding pressure is reduced by stopping the drive source during idling stop control. Even if it does not occur, it is possible to eliminate the need for another clamping pressure generator such as an electric oil pump.

1 is a skeleton diagram showing a vehicle equipped with an automatic transmission according to an embodiment. It is an engagement table | surface of the automatic transmission which concerns on embodiment. It is a skeleton figure which shows the vehicle carrying the modification of the automatic transmission which concerns on embodiment. It is a skeleton figure which shows the vehicle carrying the further modification of the automatic transmission which concerns on embodiment.

  Hereinafter, an embodiment of the automatic transmission 3 will be described with reference to FIG. 1A. A vehicle 1 equipped with an automatic transmission 3 includes an internal combustion engine (drive source) 2, an automatic transmission 3, an ECU 4 and a hydraulic control device 5 that control the automatic transmission 3, wheels 8 </ b> L, 8 </ b> R, and the like. Yes. The internal combustion engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine, and is connected to the automatic transmission 3. In the present embodiment, the automatic transmission 3 is a so-called FF (front engine / front drive) type. However, the automatic transmission 3 is not limited to the FF type, and may be an FR (front engine / rear drive) type.

  The automatic transmission 3 includes an input shaft 30 of the automatic transmission 3, a starting device 10, a continuously variable transmission mechanism 40, a gear train 50, a countershaft portion 60, a differential device 80, left and right drive shafts 82L, 82R and a mission case 90 that accommodates them. The automatic transmission 3 includes a first axis AX1 to a fourth axis AX4 that are parallel to each other.

  The first axis AX1 is coaxial with the crankshaft 20 of the internal combustion engine 2. On the first shaft AX1, there are an input shaft 30 that is drivingly connected to the crankshaft 20, a starting device 10, an intermediate shaft 31 that is connected to the output side of the starting device 10, and a second clutch that is attached to the intermediate shaft 31. (Second engagement element) C2, the first gear 32 attached to the second clutch C2, the primary pulley 41 of the continuously variable transmission mechanism 40, and the primary shaft 47 that is the rotation shaft thereof are arranged. The second clutch C <b> 2 has an inner peripheral portion attached to the intermediate shaft 31 and an outer peripheral portion attached so as to rotate integrally with the first gear 32.

  On the second shaft AX2, a secondary pulley 42 of the continuously variable transmission mechanism 40, a secondary shaft 48 that is a rotating shaft thereof, an output shaft 33, a secondary clutch 48, and a first clutch that can engage and disengage the output shaft 33 (first clutch). Engagement element) C1, a two-way clutch (third engagement element) TWC, a second gear 34 attached to the two-way clutch TWC, and a drive gear 35 attached to the output shaft 33. The two-way clutch TWC has an inner peripheral portion attached to the output shaft 33 and an outer peripheral portion attached to rotate integrally with the second gear 34.

  On the third axis AX3, a counter shaft 61 of the counter shaft portion 60, a driven gear 62, and a drive gear 63 are arranged. A differential device 80 and left and right drive shafts 82L and 82R are disposed on the fourth axis AX4. The drive shafts 82L and 82R are provided with left and right wheels 8L and 8R.

  In the automatic transmission 3, the power transmission path that connects the input shaft 30 and the output shaft 33 via the continuously variable transmission mechanism 40 is referred to as a first power transmission path a1, and the first power transmission path a1 includes a first power transmission path a1. A clutch C1 is interposed. In the present embodiment, the first clutch C1 is disposed closer to the wheels 8L and 8R than the continuously variable transmission mechanism 40. The first clutch C1 has a multi-plate or single-plate friction plate that is engaged and disengaged by supplying and discharging hydraulic pressure to a hydraulic servo (not shown), and friction that connects and disconnects power transmission by engagement and disengagement between the friction plates. It is an engagement element. The first clutch C1 can be switched to an engaged state during forward travel, a disengaged state during reverse travel, and a disengaged state during inertia travel, and connects and disconnects power transmission.

  In the present embodiment, the case where the first clutch C1 that is a friction engagement element is applied as the first engagement element that can engage and disengage the secondary shaft 48 and the output shaft 33 has been described. I can't. The configuration of the first engagement element is not limited as long as power transmission can be disconnected and connected, and may be a mesh clutch, a two-way clutch, or the like in addition to the friction engagement element. In other words, the first clutch C1 is positioned between the continuously variable transmission mechanism 40 and the connecting portion on the side of the wheels 8L and 8R with respect to the first power transmission path a1 of the second power transmission path a2 described later. .

  Further, the continuously variable transmission mechanism 40 and the first clutch C1 in the first power transmission path a1 are connected to the internal combustion engine 2 side, and the continuously variable transmission mechanism 40 and the wheels 8L and 8R side of the first clutch C1 are connected to the gear train. The power transmission path connected via 50 is defined as a second power transmission path a2. A two-way clutch TWC for connecting and disconnecting power transmission and a second clutch C2 disposed closer to the internal combustion engine 2 than the two-way clutch TWC are interposed in the second power transmission path a2.

  The second clutch C2 has a multi-plate or single-plate friction plate that is engaged / disengaged by supply / discharge of hydraulic pressure to a hydraulic servo (not shown), and friction that engages / disengages power transmission by engagement / disengagement between the friction plates. It is an engagement element. The second clutch C <b> 2 is disposed at a connecting portion of the second power transmission path a <b> 2 on the internal combustion engine 2 side with respect to the first power transmission path a <b> 1, and is between the intermediate shaft 31 coaxial with the input shaft 30 and the gear train 50. Is intervened. The second clutch C2 connects and disconnects power transmission by switching to the engaged state during reverse travel. In the present embodiment, the case where the second clutch C2 that is a friction engagement element is applied as the second engagement element that can engage and disengage the intermediate shaft 31 and the gear train 50 has been described. I can't. The configuration of the second engagement element is not limited as long as power transmission can be disconnected and connected, and may be a mesh clutch, a two-way clutch, or the like in addition to the friction engagement element.

  The two-way clutch TWC is disposed at a connecting portion of the second power transmission path a2 on the side of the wheels 8L and 8R with respect to the first power transmission path a1, and is interposed between the output shaft 33 and the gear train 50. The two-way clutch TWC is set to disconnect the power transmission from the output shaft 33 to the gear train 50 and to connect the power transmission from the gear train 50 to the output shaft 33. That is, the two-way clutch TWC is interposed on the wheels 8L and 8R side in the second power transmission path a2 with respect to the wheels 8L and 8R, and mechanically connects and disconnects the power transmission by engagement / disengagement due to the wedge action. The two-way clutch TWC connects and disconnects power transmission by switching to a disengaged state at least when the second clutch C2 is engaged during forward travel and to an engaged state during reverse travel.

  The starting device 10 includes a torque converter 11 and a lock-up clutch 12 that can lock it up. The torque converter 11 is drivingly connected to the continuously variable transmission mechanism 40 via the intermediate shaft 31. The torque converter 11 is disposed between a pump impeller 11a connected to the input shaft 30 of the automatic transmission 3, a turbine runner 11b to which rotation of the pump impeller 11a is transmitted via oil as a working fluid. And a stator 11c whose rotation is restricted in one direction by a one-way clutch 11d fixed to the case 90. The turbine runner 11 b is connected to the intermediate shaft 31. The lockup clutch 12 can engage and disengage the front cover 12a and the intermediate shaft 31, and can switch the torque converter 11 between a lockup state and an unlockup state.

  The continuously variable transmission mechanism 40 can continuously change the gear ratio, and in this embodiment, a belt-type continuously variable automatic transmission mechanism is applied. However, the present invention is not limited to this, and as the continuously variable transmission mechanism 40, for example, a toroidal continuously variable transmission mechanism, a cone ring continuously variable transmission mechanism, or the like may be applied. The continuously variable transmission mechanism 40 includes a primary pulley 41 disposed on the first shaft AX1, a secondary pulley 42 disposed on the second shaft AX2, and an endless belt wound around the pulleys 41 and 42. (Including all endless belts such as metal push type belts, metal pull type belts, metal rings, etc.) 43.

  The primary pulley 41 has conical wall surfaces that are opposed to each other, and a fixed sheave 41 a that is fixed so as not to move in the axial direction with respect to the primary shaft 47, and is movable in the axial direction with respect to the primary shaft 47. The movable sheave 41b is supported, and the belt 43 is sandwiched by a groove portion having a V-shaped cross section formed by the fixed sheave 41a and the movable sheave 41b.

  The secondary pulley 42 has conical wall surfaces that are opposed to each other, and a fixed sheave 42 a that is fixed so as not to move in the axial direction with respect to the secondary shaft 48, and is movable in the axial direction with respect to the secondary shaft 48. The movable sheave 42b is supported, and the belt 43 is sandwiched by a groove portion having a V-shaped cross section formed by the fixed sheave 42a and the movable sheave 42b. The fixed sheave 41 a of the primary pulley 41 and the fixed sheave 42 a of the secondary pulley 42 are arranged so as to be opposite to the belt 43 in the axial direction.

  A hydraulic servo 45 is disposed on the back side of the movable sheave 41 b of the primary pulley 41, and a hydraulic servo 46 is disposed on the back side of the movable sheave 42 b of the secondary pulley 42.

  The gear train 50 is provided by connecting the second clutch C2 and the two-way clutch TWC. The gear train 50 includes a first idler gear (idler gear) 51 that meshes with the first gear 32, and a second idler gear (idler gear) 52 that meshes with each of the first idler gear 51 and the second gear 34. Have. That is, the gear train 50 includes a plurality of idler gears that reversely rotate the input shaft 30 and transmit it to the output shaft 33.

  In the first power transmission path a1, the first clutch C1 is connected to the continuously variable transmission mechanism 40 and the second power transmission path a2 on the side of the wheels 8L and 8R with respect to the first power transmission path a1, that is, the two-way. It is located between the clutch TWC.

  The counter shaft portion 60 includes a counter shaft 61, a driven gear 62 and a drive gear 63 that rotate integrally with the counter shaft 61. The driven gear 62 meshes with the drive gear 35. The drive gear 63 has a smaller diameter than the driven gear 62 and meshes with the ring gear 83 of the differential device 80.

  The differential device 80 has a differential case 81 containing a differential gear, and the differential case 81 has a ring gear 83 having a relatively large diameter fixed thereto. The ring gear 83 is connected to a differential gear via a differential case 81, and left and right drive shafts 82L and 82R supported by the differential case 81 are connected via a differential gear. Therefore, the output rotation that is continuously variable by the continuously variable transmission mechanism 40 is transmitted to the differential device 80 via the counter shaft portion 60, and the differential device 80 absorbs the differential rotation of the left and right drive shafts 82L and 82R. It is output to the wheels 8L and 8R connected to the left and right drive shafts 82L and 82R. That is, the output shaft 33 is drivingly connected to the wheels 8L and 8R.

  The ECU 4 includes, for example, a CPU, a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port. Various control signals such as a control signal to the hydraulic control device 5 are provided. The signal is output from the output port. Further, the ECU 4 can switch the automatic transmission 3 between the forward mode and the reverse mode based on the travel stop state of the vehicle 1 and the driver's intention of acceleration / deceleration.

  The hydraulic control device 5 includes, for example, a valve body, generates a line pressure, a modulator pressure, and the like from the hydraulic pressure supplied from an oil pump (not shown). Based on a control signal from the ECU 4, the first clutch C 1, The hydraulic pressure for controlling the two-clutch C2, the continuously variable transmission mechanism 40, and the lock-up clutch 12 can be supplied and discharged.

  The automatic transmission 3 configured as described above moves forward by disengaging the first clutch C1 and the second clutch C2 shown in the skeleton diagram of FIG. 1A in the combination shown in the engagement table of FIG. 1B. Either mode or reverse mode is selected and achieved, or none is selected and the neutral state is entered. In FIG. 1B, “(◯)” is connected from the internal combustion engine 2 side to the wheels 8L and 8R side in reverse, but disconnected from the wheels 8L and 8R side to the internal combustion engine 2 side. The engine brake is not activated.

  Thus, the ECU 4 puts the first clutch C1 in the engaged state and the second clutch C2 in the released state, and the two-way clutch TWC is mechanically disconnected (released state) instead of being judged by the ECU 4, A forward mode in which the vehicle travels forward can be executed by transmitting the driving force of the internal combustion engine 2 from the input shaft 30 to the output shaft 33 via the first power transmission path a1. In addition, the ECU 4 puts the first clutch C1 in the disengaged state and the second clutch C2 in the engaged state, and the two-way clutch TWC is in the mechanically connected state (engaged state) instead of being judged by the ECU 4, and the internal combustion engine By transmitting the driving force of the engine 2 from the input shaft 30 to the output shaft 33 via the second power transmission path a2, it is possible to execute a reverse mode in which the vehicle travels backward. Moreover, the ECU 4 is inertial by disengaging the first clutch C1 and disengaging at least one of the second clutch C2 and the two-way clutch TWC and disengaging the power transmission between the input shaft 30 and the output shaft 33. It is possible to execute a cutting mode capable of traveling. In the present embodiment, in the disengagement mode, the ECU 4 disengages the power transmission between the continuously variable transmission mechanism 40 and the wheels 8L and 8R by disengaging the first clutch C1 and disengaging the two-way clutch TWC. This enables inertial running. In the present embodiment, the forward mode is used exclusively during forward travel, and the reverse mode is used exclusively during reverse travel.

  Next, the operation of the automatic transmission 3 described above will be described.

  When the vehicle 1 travels forward with the driving force of the internal combustion engine 2 after the internal combustion engine 2 is started, the ECU 4 selects the forward mode, engages the first clutch C1, and releases the second clutch C2. Put it in a state. As a result, the driving force of the internal combustion engine 2 is transmitted from the input shaft 30 to the intermediate shaft 31 via the starting device 10 and input to the primary pulley 41. At this time, since the second clutch C2 is in the released state, the rotation of the intermediate shaft 31 is not transmitted to the gear train 50.

  The rotation of the primary pulley 41 is transmitted to the secondary pulley 42 via the belt 43 and input to the first clutch C1. At this time, since the first clutch C1 is in the engaged state, the rotation of the secondary shaft 48 is transmitted to the output shaft 33. Since the two-way clutch TWC is set so as to cut off the power transmission from the output shaft 33 to the gear train 50, the rotation of the output shaft 33 is transmitted to the drive gear 35 without being transmitted to the gear train 50. . The rotation of the drive gear 35 is transmitted to the differential device 80 via the counter shaft portion 60, and is transmitted from the left and right drive shafts 82L and 82R to the wheels 8L and 8R. Thus, the automatic transmission 3 enters the forward mode, and the driving force of the internal combustion engine 2 is transmitted to the wheels 8L and 8R via the first power transmission path a1.

  Next, when the vehicle 1 travels forward by inertia regardless of the driving force of the internal combustion engine 2 during idling or after the internal combustion engine 2 is stopped, the ECU 4 uses the engine brake or coasts in the neutral state. That is, it is determined whether to select a cutting mode. When the ECU 4 determines that the engine brake is to be used, the first clutch C1 is engaged, the second clutch C2 is released, and the lockup clutch 12 is engaged. Thereby, the rotation from the wheels 8L, 8R is transmitted to the drive gear 35 and the output shaft 33 via the differential device 80 and the counter shaft portion 60. Also at this time, the rotation of the output shaft 33 is not transmitted to the gear train 50 by the two-way clutch TWC but is input to the continuously variable transmission mechanism 40 via the first clutch C1. The rotation of the continuously variable transmission mechanism 40 is reversely input to the internal combustion engine 2 via the intermediate shaft 31 and the lockup clutch 12, and the engine brake is activated.

  Further, when the ECU 4 selects the disconnection mode and determines that the automatic transmission 3 is in the neutral state and coasts, the first clutch C1 and the second clutch C2 are released. Thereby, the rotation from the wheels 8L and 8R is transmitted to the drive gear 35 and the output shaft 33 via the differential device 80 and the counter shaft portion 60, but the rotation of the output shaft 33 is transmitted to the continuously variable transmission mechanism 40 and the gear train. In the automatic transmission 3, inertial running is realized without receiving a large braking force.

  Next, when the vehicle 1 travels backward by the driving force of the internal combustion engine 2, the ECU 4 selects the reverse mode, puts the first clutch C1 into the released state, and puts the second clutch C2 into the engaged state. As a result, the driving force of the internal combustion engine 2 is transmitted from the input shaft 30 to the intermediate shaft 31 via the starting device 10, and is transmitted to the gear train 50 because the second clutch C2 is in the engaged state. Accordingly, the rotation of the second clutch C2 is transmitted to the two-way clutch TWC via the first idler gear 51 and the second idler gear 52. Since the two-way clutch TWC is set to connect power transmission from the gear train 50 to the output shaft 33, rotation from the gear train 50 is transmitted from the output shaft 33 to the drive gear 35. The rotation of the drive gear 35 is transmitted to the differential device 80 via the counter shaft portion 60, and is transmitted from the left and right drive shafts 82L and 82R to the wheels 8L and 8R. On the other hand, the rotation of the intermediate shaft 31 is input to the primary pulley 41 and the secondary pulley 42 is rotated, but the rotation is not transmitted to the output shaft 33 because the first clutch C1 is in the released state. Thus, the automatic transmission 3 enters the reverse mode, and the driving force of the internal combustion engine 2 is transmitted to the wheels 8L and 8R through the second power transmission path a2.

  As described above, according to the automatic transmission 3 of the present embodiment, the first clutch C1 includes the continuously variable transmission mechanism 40 and the wheels 8L of the second power transmission path a2 with respect to the first power transmission path a1. , 8R side connecting portion, and can be switched to a released state during coasting. For this reason, during idling stop control before deceleration during deceleration, by selecting and executing the cutting mode, the internal combustion engine 2 and the continuously variable transmission mechanism 40 are stopped while the wheels 8L and 8R are rotating. The belt of the speed change mechanism 40 can be prevented from slipping. As a result, the forward traveling using the continuously variable transmission mechanism 40 and the reverse traveling using the gear train 50 without using the continuously variable transmission mechanism 40 can be switched, but the internal combustion engine 2 is stopped during idling stop control. Even when the clamping pressure is not generated, another clamping pressure generating unit such as an electric oil pump can be omitted.

  Further, since the first clutch C1 is interposed on the wheels 8L and 8R side from the continuously variable transmission mechanism 40, the forward clutch travels in the neutral state in which the first clutch C1 is in the released state, that is, the disconnect mode. Sometimes, rotation from the wheels 8L, 8R side is not transmitted to the continuously variable transmission mechanism 40. For this reason, the deceleration can be further reduced as compared with the case where the continuously variable transmission mechanism 40 is rotated during inertial traveling.

  In the automatic transmission 3 according to the present embodiment, the first clutch C1 includes the continuously variable transmission mechanism 40 and the first power transmission path of the second power transmission path a2 in the first power transmission path a1. It is located between the wheel 8L and the connecting portion on the 8R side with respect to a1. For this reason, during the forward traveling, the impact torque is absorbed by the first clutch C1 before the input of the impact torque generated during the rough road traveling from the wheels 8L and 8R side reaches the continuously variable transmission mechanism 40. Can (torque fuse). For this reason, the occurrence of belt slip that can occur when the impact torque reaches the continuously variable transmission mechanism 40 can be suppressed. Further, while the vehicle is stopped, the second clutch C2 can be disengaged and the continuously variable transmission mechanism 40 can shift the speed, and for example, a second speed start can be realized.

  Here, for example, as in Patent Document 1, when the reverse clutch is arranged on the second shaft, the reverse clutch arranged on the second shaft outputs the driving force from the gear train during the reverse movement to the output shaft. Since the transmission torque is large, the friction plate has a large number of friction plates, or the friction plate has a large diameter. For this reason, there is a problem that when the reverse clutch is released during forward movement, drag resistance increases with respect to the rotation of the output shaft, resulting in poor fuel consumption.

  On the other hand, in the automatic transmission 3 according to the present embodiment, the second clutch C2 is interposed on the internal combustion engine 2 side of the two-way clutch TWC in the second power transmission path a2, so that the second clutch Compared to the case where C2 is arranged on the first power transmission path a1 on the wheels 8L, 8R side than the continuously variable transmission mechanism 40, the transmission torque required for the second clutch C2 can be reduced. As a result, the friction plate of the second clutch C2 can be reduced or the friction plate can be reduced in diameter, so that the drag resistance against the rotation of the output shaft 33 can be reduced when the clutch is released during advance. Therefore, according to the automatic transmission 3, while the forward travel using the continuously variable transmission mechanism 40 and the reverse travel using the gear train 50 can be switched, the second clutch C2 for reverse travel at the time of forward travel can be switched. Drag resistance can be reduced.

  In the automatic transmission 3 of the present embodiment, the second clutch C <b> 2 is interposed between the intermediate shaft 31 coaxial with the input shaft 30 and the gear train 50. For this reason, since the second clutch C2 can be arranged on the first power transmission path a1 on the input shaft 30 side, the first clutch on the input shaft 30 side when the second clutch C2 is disengaged during forward movement. The number of gears of the gear train 50 that is rotated by the power transmission from the power transmission path a1 can be minimized. For this reason, generation | occurrence | production of the rotation resistance by gear accompanying rotation can be suppressed.

  In the second power transmission path a2, the required torque is often the smallest on the input shaft 30 side, and therefore the second clutch C2 is disposed on the first power transmission path a1 on the output shaft 33 side. As compared with the above, the transmission torque required for the second clutch C2 can be minimized, the friction plate of the second clutch C2 can be greatly reduced, or the diameter of the friction plate can be greatly reduced, The drag resistance against the rotation of the output shaft 33 at the time can be further reduced.

  In the automatic transmission 3 of the present embodiment described above, the case where the two-way clutch TWC is used as the third engagement element has been described, but the present invention is not limited to this. That is, the third engagement element may be any element that is interposed on the wheels 8L and 8R side of the second power transmission path a2 with respect to the wheels 8L and 8R and connects and disconnects the power transmission. A dog clutch to be detached or a friction engagement element may be applied.

  Further, in the automatic transmission 3 according to the present embodiment, the two-way clutch TWC is disposed at a connection portion of the second power transmission path a2 on the side of the wheels 8L and 8R with respect to the first power transmission path a1, and the output shaft 33 Although the case of being interposed between the gear train 50 has been described, the present invention is not limited to this. For example, as shown in FIG. 2, the two-way clutch TWC1 is provided on the same axis as the intermediate shaft 31 so as to be connected adjacent to the wheels 8L and 8R from the second clutch C2 in the second power transmission path a2. Also good. That is, the two-way clutch TWC1 may be interposed between the second clutch C2 and the gear train 50. In this case, the two-way clutch TWC1 is set to cut power transmission from the output shaft 33 side to the input shaft 30 side and to connect power transmission from the input shaft 30 side to the output shaft 33 side. When the vehicle 1 moves forward, the rotation of the output shaft 33 is transmitted to the gear train 50 but is not transmitted to the second clutch C2. In this case as well, even when the internal combustion engine 2 is stopped during idling stop control, it is possible to eliminate the need for another clamping pressure generator, and to reduce the transmission torque required for the second clutch C2. Since it can be made smaller, drag resistance against rotation of the output shaft 33 during forward movement can be reduced.

  Alternatively, as shown in FIG. 3, the two-way clutch TWC <b> 2 may be interposed between the gear trains 50, for example, between the first idler gear 51 and the second idler gear 52. In this case, the two-way clutch TWC2 is set to disconnect the power transmission from the output shaft 33 side to the input shaft 30 side and to connect the power transmission from the input shaft 30 side to the output shaft 33 side. When the vehicle 1 moves forward, the rotation of the output shaft 33 is transmitted halfway through the gear train 50, but is not transmitted to the second clutch C2. In this case as well, even when the internal combustion engine 2 is stopped during idling stop control, it is possible to eliminate the need for another clamping pressure generator, and to reduce the transmission torque required for the second clutch C2. Since it can be made smaller, drag resistance against rotation of the output shaft 33 during forward movement can be reduced.

  In the automatic transmission 3 according to the present embodiment, the case where the second clutch C2 is interposed between the intermediate shaft 31 and the gear train 50 has been described, but the present invention is not limited thereto. For example, the second clutch C <b> 2 may be provided in the middle of the gear train 50. In either case, compared with the case where the second clutch C2 is interposed between the output shaft 33 and the gear train 50, the transmission torque required for the second clutch C2 can be reduced, and the second The friction plate of the clutch C2 can be reduced, or the friction plate can be reduced in diameter, and drag resistance against rotation of the output shaft 33 during forward movement can be reduced.

  The present embodiment includes at least the following configuration. The automatic transmission (3) of the present embodiment includes an input shaft (30) that is drivingly connected to a drive source (2) of a vehicle (1), and an output shaft (33) that is drivingly connected to wheels (8L, 8R). ), A continuously variable transmission mechanism (40) capable of continuously changing the gear ratio, and the input shaft (30) and the output shaft (33) are connected via the continuously variable transmission mechanism (40). A first engagement element (C1), which is interposed in one power transmission path (a1), and switches to an engaged state during forward travel and a released state during reverse travel, and the first engagement element (C1) The continuously variable transmission mechanism (40) and the first engagement element (C1) side of the continuously variable transmission mechanism (40) and the first continuously variable transmission mechanism (40) and the first engagement in the power transmission path (a1). Second power transmission for connecting the wheel (8L, 8R) side of the element (C1) via the gear train (50). In the path (a2), a second engagement element (interlocked between the input shaft (30) and the gear train (50)) that cuts power transmission by switching to an engaged state during reverse travel. C2) and the second engagement element (C2) in the second power transmission path (a2) on the side of the wheels (8L, 8R), and at least the second engagement element during forward traveling A third engagement element (TWC, TWC1, TWC2) for connecting and disconnecting power transmission by switching to the disengaged state when (C2) is in the engaged state and to the engaged state during reverse travel; The first engaging element (C1) includes the continuously variable transmission mechanism (40) and the wheels (8L, 8R) with respect to the first power transmission path (a1) of the second power transmission path (a2). It is located between the connecting part on the side and inertia It is switchable to the release state when the row. According to this configuration, the first engagement element (C1) includes the continuously variable transmission mechanism (40) and the wheels (8L, 8) to the first power transmission path (a1) of the second power transmission path (a2). 8R) and a connecting portion on the side, and can be switched to a released state during coasting. For this reason, during idling stop control before stopping during deceleration, by switching the first engagement element (C1) to the released state, the wheels (8L, 8R) rotate while the drive source (2) and the continuously variable Since the speed change mechanism (40) stops, the belt of the continuously variable speed change mechanism (40) can be prevented from slipping. As a result, it is possible to switch between forward travel using the continuously variable transmission mechanism (40) and reverse travel using the gear train (50) without using the continuously variable transmission mechanism (40). Even if the clamping pressure is not generated by stopping the drive source (2), it is possible to eliminate the need for another clamping pressure generating part such as an electric oil pump.

  The first engagement element (C1) includes a continuously variable transmission mechanism (40) and a first power transmission path (a2) of the first power transmission path (a1) (a1). and a connecting portion on the side of the wheel (8L, 8R) with respect to a1). For this reason, during forward traveling, the impact torque due to sudden braking from the wheels (8L, 8R) side is absorbed by the first engagement element (C1) before reaching the continuously variable transmission mechanism (40). can do. Thereby, generation | occurrence | production of the belt slip which can occur when an impact torque has reached the continuously variable transmission mechanism (40) can be suppressed.

  Further, since the driving force is output via the gear train (50) during reverse travel, it is not necessary to control the continuously variable transmission mechanism (40) during reverse travel, and the control by the ECU (4) is simplified. Can do. Furthermore, since the generation of the clamping pressure is unnecessary at that time, the required hydraulic pressure becomes smaller than when the clamping pressure is generated, and the load on the drive source (2) can be reduced.

  In addition, the second engagement element (C2) that is engaged when moving backward and released when moving forward is more than the third engagement element (TWC, TWC1, TWC2) in the second power transmission path (a2). Is also interposed on the drive source (2) side. For this reason, compared with the case where the second engagement element (C2) is disposed in the first power transmission path (a1) on the side of the wheels (8L, 8R) from the continuously variable transmission mechanism (40), The transmission torque required for the second engagement element (C2) can be reduced. As a result, the friction plate of the second engagement element (C2) can be reduced or the friction plate can be reduced in diameter, so that the drag resistance against the rotation of the output shaft (33) can be reduced when released in advance. Can be small. Therefore, according to this automatic transmission (3), it is possible to switch between forward travel using the continuously variable transmission mechanism (40) and reverse travel using the gear train (50), but for reverse travel during forward travel. The drag resistance of the second engagement element (C2) can be reduced.

  In addition, since the second engagement element (C2) is interposed between the input shaft (30) and the gear train (50), the second engagement element (C2) is connected to the first power transmission path ( a1), and when the second engagement element (C2) is in the released state during forward movement, it is rotated by the power transmission from the first power transmission path (a1) on the input shaft (30) side. The number of gears in the gear train (50) can be minimized. For this reason, generation | occurrence | production of the rotation resistance by gear accompanying rotation can be suppressed. In the second power transmission path (a2), since the required torque is often the smallest on the input shaft (30) side, the second engagement element (C2) is the first on the output shaft (33) side. The transmission torque required for the second engagement element (C2) can be minimized as compared with the case where it is arranged in the power transmission path (a1), and the friction of the second engagement element (C2) The plate can be greatly reduced, or the diameter of the friction plate can be greatly reduced, and the drag resistance against the rotation of the output shaft (33) during forward movement can be further reduced.

  In the automatic transmission (3) of the present embodiment, the first engagement element (C1) is in the engaged state, and the third engagement element (TWC, TWC1, TWC2) is in the released state. A forward mode capable of traveling forward by transmitting the driving force of the driving source (2) from the input shaft (30) to the output shaft (33) via the first power transmission path (a1); The drive source with the first engagement element (C1) in the released state, the second engagement element (C2) in the engagement state, and the third engagement element (TWC, TWC1, TWC2) in the engagement state A reverse mode capable of reverse travel by transmitting the driving force of (2) from the input shaft (30) to the output shaft (33) via the second power transmission path (a2); The engagement element (C1) is released, the second engagement element (C2) and the third engagement element (C1) In a cutting mode in which inertial running is possible by disengaging at least one of the coupling elements (TWC, TWC1, TWC2) and cutting the power transmission between the input shaft (30) and the output shaft (33). Switching is possible. According to this configuration, since the forward / reverse operation can be switched only by switching between the forward mode and the reverse mode, it is not necessary to use a forward / reverse switching mechanism using a planetary gear, for example, and the configuration can be simplified.

  In the automatic transmission (3) of the present embodiment, the third engagement element (TWC, TWC1, TWC2) is a two-way clutch. According to this configuration, the power transmission can be connected / disconnected by the wedge action or the engagement / disengagement, so that the energy supplied from the outside for the connection / disconnection operation can be reduced as compared with the case of using the clutch operated by hydraulic pressure or electric power. It can be made unnecessary and fuel consumption can be improved.

  In the automatic transmission (3) of the present embodiment, the third engagement elements (TWC, TWC1, TWC2) can be meshing clutches. According to this configuration, the transmission torque at the time of engagement can be increased, and the power transmission can be reliably cut at the time of release.

  In the automatic transmission (3) according to the present embodiment, the gear train (50) reverses the rotation of the input shaft (30) and transmits it to the output shaft (33). 52). According to this configuration, it is not necessary to use a planetary gear having a complicated configuration as the gear train (50), and thus the configuration can be simplified.

  The automatic transmission can be used for an automatic transmission having a transmission mechanism having a continuously variable transmission mechanism capable of continuously changing a transmission gear ratio, and in particular, an input shaft and an output shaft without using a continuously variable transmission mechanism. Are suitable for those that can be connected.

1 Vehicle 2 Internal combustion engine (drive source)
3 Automatic transmissions 8L, 8R Wheel 30 Input shaft 33 Output shaft 40 Continuously variable transmission mechanism 50 Gear train 51 First idler gear (idler gear)
52 Second idler gear (idler gear)
a1 First power transmission path a2 Second power transmission path C1 First clutch (first engagement element)
C2 second clutch (second engagement element)
TWC, TWC1, TWC2 Two-way clutch (third engagement element)

Claims (5)

An input shaft drivingly connected to a drive source of the vehicle;
An output shaft drivingly connected to the wheels;
A continuously variable transmission mechanism capable of continuously changing the gear ratio;
It is interposed in a first power transmission path that connects the input shaft and the output shaft via the continuously variable transmission mechanism, and connects power transmission by switching to an engaged state during forward traveling and a released state during backward traveling. A first engagement element to be disconnected;
The continuously variable transmission mechanism and the first engagement element in the first power transmission path on the drive source side of the first transmission element and the continuously variable transmission mechanism and the wheel side of the first engagement element via a gear train. A second engagement element that is interposed between the input shaft and the gear train in a second power transmission path that is connected to the power transmission path, and that connects and disconnects the power transmission by switching to an engagement state during reverse travel;
In the second power transmission path, it is interposed on the wheel side of the second engagement element, and when traveling forward, at least when the second engagement element is engaged, it is disengaged, and when traveling backward, it is engaged. A third engagement element for connecting and disconnecting power transmission by switching to a combined state,
The first engagement element is located between the continuously variable transmission mechanism and the connecting portion on the wheel side of the second power transmission path with respect to the first power transmission path, and during inertial traveling. An automatic transmission that can be switched to a released state. The first engagement element is engaged and the third engagement element is released, and the driving force of the drive source is transmitted from the input shaft to the output shaft via the first power transmission path. Forward mode that allows you to travel forward,
The drive force of the drive source is changed from the input shaft to the output shaft with the first engagement element in the released state, the second engagement element in the engagement state, and the third engagement element in the engagement state. A reverse mode in which the vehicle can travel backward by transmitting through the second power transmission path,
The first engagement element is in a released state, at least one of the second engagement element and the third engagement element is in a released state, and power transmission between the input shaft and the output shaft is cut off. The automatic transmission according to claim 1, wherein the automatic transmission can be switched to a cutting mode capable of coasting.   The automatic transmission according to claim 1 or 2, wherein the third engagement element is a two-way clutch.   The automatic transmission according to claim 1 or 2, wherein the third engagement element is a meshing clutch.   The automatic transmission according to any one of claims 1 to 4, wherein the gear train includes a plurality of idler gears that reversely rotate the input shaft and transmit the rotation to the output shaft.

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